Successful cast iron repair.

[larryh]

Hello all,

I guess it was on another board I posed the question of any successful repairs to broken cast iron parts. I have been working on my William and Mary Console and in the process I discovered a break in the cast iron support to the horn on the lower end of the pipe it rides on. I may have done it when it tipped of a box I had it on, or it may have been their previous and I just didn't know it. Either way the break was odd because the pieces were off by about a quarter inch. The horn part being almost below the piece attached to the pivoting pipe it rides on. I ask at some local shops about the success of trying to have it welded but they discouraged that due to the fact the cast iron piece was evidently soldered to the horn and heating it would cause it to possibly turn loose. So I was left with looking at glues, which frankly I had tried with not too great a success on some other projects. However I found a two part epoxy by Permatex called Perma Poxy. It was listed as a 4 minute grab epoxy. You have to mix two tubes together to get a hardening going, then apply it to both pieces and clamp at once. I had a bit of trouble getting the under stain pieces to line up quickly but finally with a small metal clamp and a small wood block clamp I was able to get it to look pretty close to where it belonged and tightened together well. I let it sit over night and was afraid it would just pop apart when the clamps were removed. But to my surprise so far its stayed nicely. After seeing how strong it was when set I thought about adding a washer under where the crack is and gluing it for a day to be sure that no downward stress would pop it apart again. But I didn't like the idea of the glued on washer and left it go for now. So far 4 days later its feeling quite snug against the part and it would seem in use it only really stabilizes the the horn on the lower end and supports the reproducer as well to a degree.

It would seem to be a good choice for those cracked or broken cast iron pivots seen on many electrical era machines. I had one victor that had a broken rear support and this would have worked well on it I am sure. I used JB weld on it, but I think this product would have suited the job even better. I have a photo here of the repair, you can just make out the seam where its glued and holding so far..

Larry

[Aaron]

I have never tried the JB Weld on any cast iron parts, but i have had success repairing them. My fathers friend is a jewler, and have a laser solder capable of may tasks. He has fixed a few Edison Cylinder Tone Arms for me in the past with it. Theres a space in which the part needs to be place, the jewlers hand go in, he looks through eyes pieces, and solders the piece. The only problem is, most phono piece dont fit in the space and cant be fixed. We got one tone arm in, and almost didnt get it out. Good Luck!

Aaron

[larryh]

Yes the one welder I talked with did say that a specialist with the right talent could perhaps solder the joint without damage to the rest. But a normal welding type worker he thought was iffy at best. Thus the use of the glue. I think off hand it worked better than JB weld, which I have also used.

[JohnM]

Cast-iron isn't welded, it is brazed -- which is the melting of a second metal, a brass alloy -- to 'glue' the broken pieces together. Brazing is similar to very high temperature soldering. Welding actually melts the materials being joined.

The key to successful epoxy use is making sure the proportions of A to B are correct.

[Steve Stephens]

Here's a good article on WELDING cast iron. Welding iron is done but it's not nearly as easy nor done the same way as welding steel.

http://www.lincolnelectric.com/knowledg ... reheat.asp

Steve

[JohnM]

Well, I wasn't aware that could be done! Sounds like a royal PITA at any rate, and likely not suited for things as small or finessé-y as phonograph castings! Thanks for enlightening me, though! I've only had one piece of cast-iron repaired ever and that was a Victor III mainspring support arbor that was snapped in two (this was back in the early 1970's when original parts were more difficult to obtain). The guy that fixed it for me brazed it and told me then that is how cast-iron is repaired. Once I ground away the slag, it was a very neat repair. The article on welding cast-iron describes cracks forming along the repair, etc. I still think brazing is the way to go for small parts since the metal doesn't have to get as hot as when welding and actually melting the two halves back together.

[larryh]

Yes cast iron is very touchy and repairs can be iffy. From what the farm type welders around me say it somewhat dependent on the quality of the cast iron and how much strain the break has to handle. They do have special welding rods and torches for cast iron, but still the results are often iffy. So far, although the piece isn't yet in use, it seems to be pretty strong. Once I get the cabinet top fixed for the second time, I will be ready to give it some trial runs and see if it stand the up and down of the rod ok. I don't see why it shouldn't.